TIN YAT (CHOW YUN FAT) who is an extraterrestrial comes to Earth accidentally. Just when he is about to die from lack of water, KWOK HAK CHUNG (LEUNG CHIU WAI) arrives and saves him. Meanwhile, YAT from time to time, secretly makes use of his superpower to help CHUNG in becoming better off. With the passage of time, CHUNG finds that the distance between he and his girlfriend HEUNG HO YAN (CHAN MAN YEE), whom he has known since childhood is getting further and further. They split and CHUNG goes after another rich girl CHEUGN SZE MAN (CHONG CHING YEE). YAT feels sorry for YAN and gives her special care. Their mutual, warm feelings towards each other gradually spark off the love between them. YAT is very confused. He Knows that he could not stay on Earth for long. One day, he would evaporate. Should he or should he not develop this romance?